Degree of Polymerization as Evidence of the Damage to Cotton in Mechanical Processing

Krieble, James G.; Whitwell, John C.

doi:10.1177/004051754901900903

Cited by 12 publications

(30 citation statements)

References 8 publications

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“…Confidence limits of the slope at this level will, therefore, be It has been noted earlier that Krieble's value [9] for the Empire cotton sample, 7.268, was well within this range.…”

Section: Pczyallelism Of Lines For Separate Samplesmentioning

confidence: 52%

“…of the solution was transferred to the viscometer, also in a thermostat, and times of flow measured under different applied stresses. Values of the viscosity-counterpart, & S c a r o n ; , were calculated and, subsequently, values of the intrinsic viscosity were obtained from the relationship of log &scaron;sp/ C vS. concentration, following the method of Krieble [9].…”

Section: Laboratory Experimentsmentioning

confidence: 99%

“…In the work presented here, special attention was given to the action of the beaters in the picking operation, since previous evidence showed [9] that this operation was the most drastic in causing degradation. The Saco-Lowell Shops processed the cotton to provide information on the effects of beater type, speed (r.p.m.…”

mentioning

confidence: 99%

“…It has also been argued that lack of inclusion of studies of the D.P. of wastes in the original work [9] invalidates the conclusions, on the basis that high molecular weight materials might have been concentrated in the wastes. However, it is known that immature fibers are concentrated in the picker wastes, and the work of Hessler, Merola, and Berkley [7] indicates the molecular weight of the cellulose in immature fibers to be about half that of mature fibers obtained from the same source.…”

mentioning

confidence: 99%

“…No comparison of the Krieble [9] and A.S.T.M. methods [1,4] has previously been reported, because of restrictions on sample concentration by the A.S.T.M.…”

mentioning

confidence: 99%

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Degradation of Cellulose During Mechanical Processing

Whitwell

Lemiszka

Hughes

1951

Textile Research Journal

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Previous work [9] on the degradation of cotton during mechanical processing has been extended to include a study of the action of the pickers under various operating conditions. The results indicate that blade and carding beater types cause different amounts of degradation, that the amount of degradation caused by a very close setting can be differentiated from that due to wider spacings, and that the speed of rotation of the beater has a degradation effect which is detectable only after several passes—i.e., several consecutive picker operations. The effect of consecutive picker operations under similar conditions of the other variables is readily discernible. IN A RECENT INVESTIGATION [9] it wassuggested that cotton degrades during the normal processing operations which convert the seed cotton to yarn. Evidence of this degradation was based upon the progressive reduction in D.P. of a given cotton as it was mechanically processed, the viscosity of cotton in cupriethylene diamine being used as an index of D.P. Hess et al. [6] and Forziati et al. [5] have also reported reduction of D.P. of cellulose during purely mechanical treatment, although the results in both of these cases were obtained on much more drastic treatments. All three of the reports cited concluded that mechanical energy could be absorbed by the cellulose and utilized to break valence bonds.In the light of these conclusions, it seemed desirable to extend the experimental work, concentrating on the damage incurred in a single operation, with specific study of controllable variables in the operation. In the work presented here, special attention was given to the action of the beaters in the picking operation, since previous evidence showed [9] that this operation was the most drastic in causing degradation. The Saco-Lowell Shops processed the cotton to provide information on the effects of beater type, speed (r.p.m.), setting, and repetition of passes through beating equipment.It has been argued that the damage during mechanical processing is not important with respect to that which occurs during later chemical processes such as kier-boiling or bleaching. However, a recent paper which reported studies on rain-grown and irrigated cottons [10] does not support this argument. Observed D.P. differences on samples from two stages of mechanical processing indicated degradation but were not large enough to be statistically significant (probably due to sensitivity of the method employed, which was entirely adequate for the purposes intended). However, after these samples of card sliver and combed yarns had been given identical scouring treatments, significant differences existed. Thus, although the data are not extensive, there is strong statistical evidence to indicate that the small changes in D.P. incurred during mechanical processing persisted and were not lost in the subsequent chemical treatments. An appreciable portion of the difference in D.P. of the two raw cottons also persisted through the mechanical and chemical treatments. Further experimen...

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“…Confidence limits of the slope at this level will, therefore, be It has been noted earlier that Krieble's value [9] for the Empire cotton sample, 7.268, was well within this range.…”

Section: Pczyallelism Of Lines For Separate Samplesmentioning

confidence: 52%

Section: Laboratory Experimentsmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

“…No comparison of the Krieble [9] and A.S.T.M. methods [1,4] has previously been reported, because of restrictions on sample concentration by the A.S.T.M.…”

mentioning

confidence: 99%

See 3 more Smart Citations

Degradation of Cellulose During Mechanical Processing

Whitwell

Lemiszka

Hughes

1951

Textile Research Journal

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Mechanochemical process in cotton cellulose fiber

Hon

Srinivasan

1983

J of Applied Polymer Sci

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SynopsisMechanical processing of cotton cellulose by means of a fiber cutter resulted in the disaggregation and defiberation of fiber bundles, shortening of fiber length, and loss of degree of polymerization. I t is evident that the mechanical energy supplied by shear forces is sufficient to cause homolytic scission of cellulose main chains. Mechanoradicals formed in the interim were verified by ESR studies. The crystallinity of cellulose was not influenced by mechanical treatments, but accessibility of the polymer was substantially increased due to the creation of new surfaces. The mechanically treated fiber inclined to proceeded oxidative chain reaction during aging. Regardless of their treatment conditions, cellulose fiber reached its limiting lower molecular weight after 100 days of aging.

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Implications of Philippoff flow curves for the determination of intrinsic viscosity of high polymer nitrocelluloses

Ziifle

1952

Journal of Colloid Science

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Degree of Polymerization as Evidence of the Damage to Cotton in Mechanical Processing

Cited by 12 publications

References 8 publications

Degradation of Cellulose During Mechanical Processing

Degradation of Cellulose During Mechanical Processing

Mechanochemical process in cotton cellulose fiber

Implications of Philippoff flow curves for the determination of intrinsic viscosity of high polymer nitrocelluloses

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